The present invention relates to an image processing system which connects a plurality of image forming apparatuses and an image processing apparatus that supplies image data and, more particularly, to an image processing system which connects an image processing apparatus and image forming apparatus to each other via a high-speed serial communication with a mechanism for assuring a predetermined data transfer rate, and its control method.
In recent years, in order to implement high-speed data transfer, high-speed serial communications such as IEEE1394, USB (UNIVERSAL SERIAL BUS), and the like are used in place of conventional asynchronous communication means. USB, IEEE1394, or the like has a mechanism for assuring a given data transfer rate such as the isochronous transfer mode in IEEE1394. In the isochronous transfer mode, a required number of channels that can transfer data are assured at prescribed cycle time intervals, and data are transferred via the assured channels. In this manner, an image processing system that transfers image data from an image processing apparatus such as a computer or the like to an image forming apparatus while assuring a data transfer rate corresponding to the processing performance of the apparatus can be built.
Assume that image data is sent from a single computer to a plurality of image forming apparatuses connected to that computer via isochronous communications such as high-speed serial communications so as to control them to form images in such conventional image processing system. In this case, each image forming apparatus must comprise a reception image memory for reliably receiving data sent from the computer, and its cost increases accordingly. For example, when one of the plurality of image forming apparatuses is not ready to print, if the computer begins to send data, the image forming apparatus which is not ready to print must save received data. Hence, the conventional image forming apparatus must have a memory for that purpose.
The present invention has been made in consideration of the above prior art, and has as its object to provide an image processing system and its control method, in which a computer sends print data to respective image forming apparatuses after all the image forming apparatuses become ready to output, and stops sending of the print data when any of the image forming apparatuses fails to receive data, whereby each image forming apparatus can reliably receive image data without any memory for storing image data sent from the computer, an information processing apparatus, and an image forming system control method.
In order to achieve the above object, the present invention comprises the following arrangement.
That is, there is provided an image processing system comprising an image processing apparatus and a plurality of image forming apparatuses, which are connect ed via an isochronous transfer serial bus, wherein
the image processing apparatus has image data distribution means for assuring a transfer channel and sending a data packet, and paper feed end message reception means,
each of the plurality of image forming apparatuses has image data reception means, image forming means, and paper feed end message means, and sends a paper feed end message of an image forming paper sheet to the image processing apparatus,
the image processing apparatus starts distribution of an image data packet onto the receives the paper feed end messages from all of the plurality of image forming apparatuses, and
the plurality of image forming apparatuses receive the distributed image packet and form images.
Or there is provided a method of controlling an image processing system comprising an image processing apparatus and a plurality of image forming apparatuses, which are connected via an isochronous transfer serial bus, wherein
the image processing apparatus has image data distribution means for assuring a transfer channel and sending a data packet, and paper feed end message reception means,
each of the plurality of image forming apparatuses has image data reception means, image forming means, and paper feed end message means, and sends a paper feed end message of an image forming paper sheet to the image processing apparatus,
the image processing apparatus starts distribution of an image data packet onto the isochronous transfer serial bus after the apparatus receives the paper feed end messages from all of the plurality of image forming apparatuses, and
the plurality of image forming apparatuses receive the distributed image packet and form images.
Or there is provided an image forming system comprising an image processing apparatus and image forming apparatus, which are connected via a bus which can communicate using both isochronous and asynchronous communication schemes, wherein
the image processing apparatus sends print data to the image forming apparatus using the isochronous communication scheme,
the image forming apparatus outputs an image on the basis of the print data sent from the image processing apparatus, and when the image forming apparatus must stop the output of the image, the image forming apparatus sends a message indicating that to the image processing apparatus using the asynchronous communication scheme, and
the image processing apparatus stops transmission of the print data upon reception of the message indicating that the output of the image is stopped, and sends an output stop command to the image forming apparatus using the asynchronous communication scheme.
Preferably, the image processing apparatus confirms if the image forming apparatus has already fed a paper sheet, prior to beginning of transmission of print data to the image forming apparatus.
Preferably, a plurality of image forming apparatuses are connected to the image processing apparatus, the image processing apparatus broadcasts identical print data to the plurality of image forming apparatuses, and when the image processing apparatus receives the message indicating that the output of the image is stopped from at least one of the plurality of image forming apparatuses, the image processing apparatus stops transmission of print data to all the image forming apparatuses, and sends an output stop command to all the image forming apparatuses using the asynchronous communication scheme.
Preferably, when the image processing apparatus receives the message indicating that the output of the image is stopped, the image processing apparatus pauses transmission of print data for a predetermined period of time before the image processing apparatus stops transmission of print data, and when the message indicating that the output of the image is stopped is canceled within the predetermined period of time, the image processing apparatus restarts transmission of print data.
The present invention comprises the following arrangement.
That is, there is provided a method of controlling an image forming system comprising an image processing apparatus and image forming apparatus, which are connected via a bus which can communicate using both isochronous and asynchronous communication schemes, wherein
the image processing apparatus sends print data to the image forming apparatus using the isochronous communication scheme,
the image forming apparatus outputs an image on the basis of the print data sent from the image processing apparatus, and when the image forming apparatus must stop the output of the image, the image forming apparatus sends a message indicating that to the image processing apparatus using the asynchronous communication scheme, and
the image processing apparatus stops transmission of the print data upon reception of the message indicating that the output of the image is stopped, and sends an output stop command to the image forming apparatus using the asynchronous communication scheme.
Preferably, the image processing apparatus receives messages each indicating that the image forming apparatus is ready to form an image from all the image forming apparatuses, and then starts transmission of print data.
The present invention comprises the following arrangement.
That is, there is provided an information processing apparatus connected to a plurality of image forming apparatuses, comprising:
transmission means for broadcasting print data to the plurality of image forming apparatuses;
reception means for receiving status data from each of the plurality of image forming apparatuses; and
transmission control means for controlling transmission of print data by the transmission means to the image forming apparatuses,
wherein the transmission control means controls the transmission means to start broadcast of print data upon receiving from all the image forming apparatuses status data each indicating that the image forming apparatus is ready to receive and output.
Preferably, the transmission control means pauses print data broadcast upon receiving status data indicating that print data cannot be received from some image forming apparatus during broadcast of print data to the image forming apparatuses, and restarts print data broadcast upon receiving within a predetermined period of time a message indicating that the image forming apparatus is ready to receive print data from the image forming apparatus.
Preferably, the transmission control means determines a state in which each image forming apparatus is ready to print and has completed paper feed as a state in which that image forming apparatus is ready to receive and output.
Preferably, the transmission means sends print data via a communication in an isochronous mode, and the reception means receives status data via a communication in an asynchronous mode.
Other features and advantages of the present invention will be apparent from the following description taken in conjunction with the accompanying drawings, in which like reference characters designate the same or similar parts throughout the figures thereof.